It is known that varying the temperature of a laser emitter may affect the wavelength (λ) of the emitted light. In applications where the wavelength of the laser is not critical, it is not important to precisely control the temperature of the laser emitter, and a heat sink is usually sufficient for cooling the laser emitter. However, in some applications such as Dense Wavelength Division Multiplexing (DWDM), it is important to produce light at precise wavelengths and to maintain the laser emitter at precise temperatures. For those applications, a heat sink alone is not sufficient.
Some conventional laser packages contain a large built-in temperature controller to control the temperature of the laser emitter. Some laser packages even contain an elaborate built-in coolant-circulation system for cooling the laser emitter (e.g., a laser diode). Such conventional laser emitter packages, due to their large size, cannot be easily incorporated within pluggable fiber optic transceiver modules, which typically have strict form factor requirements. Miniaturizing the built-in temperature controller, unfortunately, is not an ideal solution because small temperature controllers may not have the necessary heat transfer capability.
Accordingly, there exists a need for an apparatus for precisely controlling the temperature of a laser emitter without using a laser package that contains a large built-in temperature controller such that temperature control functionality can be implemented in an optoelectronic transceiver or transmitter module.